Lawmakers and Senate staffers worked through the weekend to find a way to provide aid to Flint, Mich., and move forward on a bipartisan energy bill. But, as of Monday, negotiations were still ongoing.

Democrats stalled debate on the energy bill last week after senators failed to agree on how to address the crisis in Flint, where corroded pipes have leached toxic levels of lead in the water supply. With the Senate set to consider a North Korea sanctions bill on Wednesday, negotiators are running out of time to reach an agreement. "I think we're closer than we were on Thursday," Sen. Maria Cantwell, D-Wash., the bill's Democratic floor manager, told reporters Monday evening.

She declined to answer whether they were considering bringing up the Flint aid as a separate bill, and not as an amendment to the energy bill. Earlier in the day she and Sen. Lisa Murkowski of Alaska, the GOP manager of the bill, said in a joint statement that they were "we are working to help advance a measure to address the Flint water crisis and hope that it will be brought up as soon as possible."

A source familiar with the discussions said it's possible the Flint aid piece could be broken out from the energy bill, a move that would allow a broader array of offsetting provisions. The available concepts will likely be discussed at Tuesday's weekly lunches to see if any of them have sufficient support to advance.

There's also an open question as to whether funding -- regardless of level -- would be best carried on the energy bill or in a separate vehicle that might be able to move more quickly through the House.

In 2014, the city switched its water supply to the Flint River to save money, but did not add chemicals to prevent pipe corrosion, so the corroded pipes leaked lead into residents’ water. As the crisis gained national attention, Michigan Democratic Sens. Debbie Stabenow and Gary Peters called for action.

They have been pushing to add an amendment to the sweeping energy bill that would provide $400 million in federal funds to fix the corroded pipes poisoning Flint and $200 million for a center for the residents who have been exposed to lead. But negotiations stalled last week, after Republicans raised what Stabenow said were "bogus excuses" regarding potential procedural issues with an amendment relating to aid.

Late last week, a Republican familiar with the sentiments of the conference suggested there might not be much wiggle room on a counter-offer made by Murkowski that was filed as a second-degree amendment Thursday. That offer would provide $50 million immediately as part of a $550 million package. Presidential politics have also permeated the debate over aid for Flint. Former Secretary of State Hillary Rodham Clinton, who is running for the Democratic nomination, left New Hampshire on Sunday to visit Flint and attend a community meeting. Stabenow and several other female senators have been supporting Clinton, and campaigned for her in New Hampshire on Friday.

"This is not merely unacceptable or wrong, though it is both. What happened in Flint is immoral," Clinton said. She called on Congress to pass an amendment granting funds to fix the city's infrastructure.

"Congress needs to pass that bill immediately," Clinton said. "This is no time for politics as usual."

Republicans have accused Democrats of politicizing the issue, particularly for blocking Murkowkski's attempt to vote on the Stabenow/Peters and Murkowski amendments.

"It's unclear why any colleague would object to her effort or why they would effective block consideration of their own amendments," Senate Majority Leader Mitch McConnell, R-Ky., said on the floor Monday. He added, "It's disappointing for our country. We're hoping our friends will reconsider."

“We had to slow it down,” Peters explained in an interview in his Senate office late Thursday. “But I’m confident that we’re going to be able to come together to hash out a deal that will be acceptable and will hopefully happen next week, first thing next week.”